Table 1 Chronology of the key scientific research and policy developments*
Year/s | Developments | Reference |
|---|---|---|
Late 1800s | Policy: There is enough medical concern about the health effects of lead contaminated water for some US authorities to regulate the lead water piping hazard. | |
1909 | Policy: Countries begin to enact bans or restrictions on the use of white lead for interior paint (eg, France, Belgium, and Austria in 1909). In 1922, the Third International Labour Conference of the League of Nations recommended the banning of white lead for interior use. | [72] |
1923 | Leaded gasoline: Tetraethyl lead begins to be sold for use in gasoline. Early production was associated with severe occupational health consequences and deaths among workers [73]. | |
1970 | Industry policy: The vehicle manufacturer General Motors announces that it would begin installing catalytic converters in its new models and that as a result it would be necessary to phase out lead in gasoline. | |
1972 | Japanese policy: Japan becomes the first country to market unleaded gasoline and by 1981 less than 3% of gasoline sold there is leaded. | [74] |
1972 | US policy: The US EPA issues rules that each gasoline station has to have at least one lead-free pump. This is to protect the platinum catalytic converter on new model vehicles to facilitate air pollution control in general (and not primarily to protect humans from lead exposure). | [65] |
1973 | US & Canadian policy: After a growing body of evidence for adverse health effects from lead toxicity [65], the US EPA announces new regulations to restrict the content of lead in gasoline. Unleaded gasoline was also introduced in Canada in the same year (1975) [74]. | [75] |
1973 | NZ advocacy: The Environmental Defence Society petitions the Clean Air Council on the topic of leaded gasoline. It is the first non-governmental organisation to campaign against lead additives [Dr Robert Mann, Personal communication, 27 September, 2007]. | |
1974 | NZ policy advocacy: The Clean Air Council (a government advisory body) calls for a phase-down of lead in gasoline. At this time the lead level was the highest in the world at 0.84 g/L [76]. Also in this year regulations were introduced in NZ that aimed to eliminate lead solder from canned foods and beverages [77]. | [12] |
1975 | NZ research: The first systematic study into lead exposure among children reports relatively high soil lead levels from the roadsides of busy urban streets. | |
1978 | NZ research: Elevated levels of lead are found in the blood of sheep grazing beside a rural highway. | |
1981 | NZ policy advocacy: The Toxic Substances Board resolves on 7 August that "...on the grounds of health hazard to some significant proportion of the population..." lead additives be deleted from gasoline as soon as practicable. | |
1983 | NZ policy advocacy: The Ministry of Energy issues a white paper on lead in gasoline, providing costs for different lead-reduction scenarios and suggesting no policy steps should be taken until the need was demonstrated by a population blood-lead survey. This year also saw the Toxic Substances Regulations that restricted the content of lead in paints used on furniture, toys, and household items [77]. | |
1984 | International/NZ research: A multi-country study that includes NZ data indicates higher levels of lead in street dust from a busy road relative to a road in a "quiet suburban area". | |
1984 | NZ research review: A comprehensive workshop at Auckland University brings together most NZ researchers on lead and other interested parties in order to plan future research programmes. | |
1984 | NZ policy: The incoming Labour Government announces on 3 August that unleaded gasoline will be available from 1986 when the extensions to the country's sole refinery are completed and a synthetic gasoline plant is operating. | |
1985 | NZ research: A study which examined house dust in a city reports "for the newer areas of the city, it was estimated that ~90% of the lead was derived from gasoline additives (via street dust and aerosol)...". | |
1986 | NZ advocacy and policy: An analysis jointly sponsored by the Government and the Royal Society of NZ strongly urges the phase-down and eventual elimination of gasoline lead. The international evidence on costs to health is acknowledged by the Ministry for the Environment in an options paper. The start of the lead phase-out begins in this year. | |
1986 | International/NZ research: A NZ scientist publishes a detailed review article on the contribution of leaded gasoline to blood lead levels. It stated that: "the weight of evidence suggests that at least one-third of blood lead comes from petrol lead". | |
1986 | NZ research: Further longitudinal study data identifies blood lead levels in children and describes some of the concerns in the international literature about possible associated cognitive deficits and behaviour problems. | |
1987 | NZ action: Leaded 91 (RON) octane gasoline is replaced by unleaded 91-octane gasoline. Higher-octane (96RON) gasoline remains leaded. | |
1988 | NZ research: Results from a longitudinal study show that blood lead levels were associated with a statistically significant increase in children's general behaviour problems. | |
1988 | NZ research: A study shows that the potential benefits of reducing leaded gasoline (eg, reduced engine wear and opportunity to use the latest engine technology) are likely to exceed any cost involved in conversion to a wholly unleaded fuel supply by 1996. | |
1988 | NZ research review. A workshop on the impact of lead in the NZ environment is held. | |
1988 | NZ research: Publications from another longitudinal study implicate various risk factors for raised lead levels, including residence near busy roads. This work reports statistically significant negative correlations between dentine lead values and all measures of school performance and ratings of inattention/restless in children. | |
1989 | International research: A summary of a report to the US Congress on childhood lead poisoning documents the relative persistence of adverse effects from neurotoxicity and on growth. | |
1990 | International research: A meta-analysis concludes that "the hypothesis that lead impairs children's IQ at low dose is strongly supported". | |
1991 | International/NZ research: A review of NZ and international data reports how lead in house dust is associated with distance from roads and also the road type (ie, traffic density). | |
1992 | NZ policy: Ministry for the Environment releases air quality guidelines. | |
1993 | NZ research: This research reports that early exposure to lead resulted in statistically detectable and apparently enduring deficits in cognitive abilities, poorer school performance and behavioural problems. | |
1993 | NZ policy review: The Ministry of Commerce produces a paper on required changes to regulations to facilitate the introduction of unleaded gasoline. | |
1994 | NZ research: The sources of lead in the atmosphere of the urban environment are estimated to be mainly automobile emissions. | |
1995 – 1996 | NZ policy: The Minister of Energy announces that no leaded gasoline will be able to be sold after 30 September, 1996. | |
Post 1996 | NZ & international research: Reports detail the reduction of lead in gasoline over the period in the decade after 1986 in NZ and associate it with declines in atmospheric lead levels and declines in population blood lead levels (ie, data for between 1984/5 and 1994 for declining blood lead levels in Christchurch residents [10]). There is also evidence for continuing reductions of blood lead levels of occupational groups involved in vehicle repairs since the lead phase-out began in 1987 [77]. |